Display screen having a graphical user interface



The FIGURE is a front view of a display screen having a graphical user interface showing my new design.

The outermost broken line rectangle shows a boundary of a display screen or portion thereof, and forms no part of the claimed design.

The broken lines within the outermost broken line rectangle show portions of the graphical user interface that form no part of the claimed design. 

CLAIM The ornamental design for a display screen having a graphical user interface, as shown and described. 